The Jupiter Theft

When the moon emerged from that cone of safety, to three-o’clock position, the ships were at the moon’s nine o’clock. But since the moon was by that time tilting its twelve inward toward the giant, the ships were still in a trailing position. With the moon at twelve o’clock, leading the whole procession, the cluster of ships was safely behind it, at the moon’s twelve o’clock. Another quarter turn for both orbiting systems put the moon at nine and the ships at three—still in the moon’s radiation shadow.

The ships’ orbits, he suspected, would have to be adjusted continually to match their period to the moon’s rotation—especially as the mass of the primary shrank. But surely, maneuvering the five ships would require only a fraction of the total energy expenditure eaten up by moving a Jovian or superjovian!

It was beautifully simple and elegant! Jameson watched in admiration for long moments.

Even the deadly probe, with its radiation backlash, was never at the crossroads of the moon’s orbit at the two points where their paths intersected. Everything ticked along beautifully.

“I see,” Jameson said. “Your ships are safe.”

The two Cygnans whistled their approval. Tetrachord wiped the screens and dropped down on four legs. One of his upper limbs twined around Triad in an almost-human gesture of affection.

Jameson blared the sharp fanfare for attention. Startled, the Cygnans jerked their heads in his direction.

“What about Earth? My planet. Will it be safe when you leave this system?”

Consternation. Much twittering back and forth. Jameson had the impression that they had never thought about it, that it hadn’t occurred to them to care.

Finally Tetrachord punched in an inquiry to the ship’s computer, or whatever passed for one aboard the Cygnan vessel. There were flashing images that made no sense to Jameson. They hadn’t bothered to adjust the screen for human vision this time.

Tetrachord twisted around. His eyestalks stretched like taffy in Jameson’s direction.

“Jameson,” the creature said. “We will cross the orbit of your planet when we leave. We will pass close to your sun and swing around it to change direction.”

Jameson got a crawly sensation down his spine. The Cygnan caravan would cross the Earth’s orbit twice.

“Just how close to Earth will you pass?” he asked.

There was no answer for a while. Jameson found he was holding his breath.

The Cygnans wouldn’t have reached anything near light-speed by the time they crossed Earth’s path, of course, so the deadly shower of X-rays that had announced their approach to the solar system would be no danger. But the probe’s deadly drive would be on. That in itself might be enough to sterilize a hemisphere if it got too close and was pointed in the wrong direction. Then, too, there was Jupiter’s own radiation belt, extending millions of miles into space. The Cygnans themselves would be safe from charged particles in the zone swept clean by their moon, but Earth might not be so fortunate.

And there certainly would be tidal effects.

Jameson trembled at the thought of what might happen if a Jupiter-sized mass passed too close to Earth. Earthquakes, floods, perhaps even the breakup of the Earth’s crust.

What if the Earth’s orbit were changed, moved a couple of million miles closer to the sun? Or pulled farther away? Or changed, like Pluto’s, to a more elliptical orbit? Earth’s climate could be permanently altered—an eternal ice age, with much of terrestrial life obliterated, or a water world, steaming under the melted polar caps!

Earth might even be plucked out of orbit to fall into the Sun.

“How close?” he repeated urgently.

“Jameson will be safe,” Triad hummed soothingly. “We will take Jameson with us.”

“Dammit!” he exploded. “That’s not what I asked! What about the Earth?”

He stopped. He’d unthinkingly used human speech.

They didn’t understand the words, but the violence of his outburst had startled them.

Triad pressed herself against her larger companion. The soft, rat-sized thing plastered to her abdomen reacted to her distress by digging in more firmly with its insectlike legs.

Tetrachord hissed reflexively at Jameson. His upper body stretched to become a foot taller.

Jameson stood facing the alien pair, fists clenched. The kitten had dropped off his lap and scurried away. After a moment, Jameson’s fists fell to his sides. The tension in the bodies of the two Cygnans gradually relaxed.

Jameson stooped over the keyboard of the Moog again and played out his question. “Where will the Earth be when you pass?”

There was a pause while they digested his query. Finally Tetrachord said, “We do not know.”

“Find out,” Jameson said. There was no Cygnan word for “please.”